Annuals, biennials or perennials. Leaf-blades flat or rolled. Inflorescence usually a simple, laterally compressed, dense spike. Spikelets solitary at each node of the tough or fragile rhachis, sessile, distichously arranged, with 2-3 bisexual florets, the rhachilla produced and bearing a further rudimentary floret; glumes linear-subulate, 1-nerved, keeled, scabrid; lemma lanceolate, 5-nerved, keeled, with rigid spines on the keel and a long, straight scabrid awn from the tip; palea 2-keeled.